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A role for mitochondrial oxidants in stress-induced premature senescence of human vascular smooth muscle cells.

Mistry Y, Poolman T, Williams B, Herbert KE - Redox Biol (2013)

Bottom Line: Angiotensin also resulted in an increase in mitoSOX fluorescence indicating stimulation of mitochondrial superoxide.Significantly, the induction of senescence by angiotensin II was abrogated by rotenone and by the mitochondria-targeted superoxide dismutase mimetic, mitoTEMPO.These data suggest that mitochondrial superoxide is necessary for the induction of stress-induced premature senescence by angiotensin II and taken together with other data suggest that mitochondrial cross-talk with NADPH oxidases, via as yet unidentified signalling pathways, is likely to play a key role.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, UK.

ABSTRACT
Mitochondria are a major source of cellular oxidants and have been implicated in aging and associated pathologies, notably cardiovascular diseases. Vascular cell senescence is observed in experimental and human cardiovascular pathologies. Our previous data highlighted a role for angiotensin II in the induction of telomere-dependent and -independent premature senescence of human vascular smooth muscle cells and suggested this was due to production of superoxide by NADPH oxidase. However, since a role for mitochondrial oxidants was not ruled out we hypothesise that angiotensin II mediates senescence by mitochondrial superoxide generation and suggest that inhibition of superoxide may prevent vascular smooth muscle cell aging in vitro. Cellular senescence was induced using a stress-induced premature senescence protocol consisting of three successive once-daily exposure of cells to 1×10(-8) mol/L angiotensin II and was dependent upon the type-1 angiotensin II receptor. Angiotensin stimulated NADPH-dependent superoxide production as estimated using lucigenin chemiluminescence in cell lysates and this was attenuated by the mitochondrial electron transport chain inhibitor, rotenone. Angiotensin also resulted in an increase in mitoSOX fluorescence indicating stimulation of mitochondrial superoxide. Significantly, the induction of senescence by angiotensin II was abrogated by rotenone and by the mitochondria-targeted superoxide dismutase mimetic, mitoTEMPO. These data suggest that mitochondrial superoxide is necessary for the induction of stress-induced premature senescence by angiotensin II and taken together with other data suggest that mitochondrial cross-talk with NADPH oxidases, via as yet unidentified signalling pathways, is likely to play a key role.

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Ang II stimulated mitochondrial superoxide production in live hVSMC. Cells were pre-incubated with Ang II (1×10−7 mol/L) for 1 h then loaded with MitoSOX (5 µmol/L) for 10 min at 37 °C. Cells were washed to remove excess probe prior to measurement of fluorescence. Bars represent mean+SD, n=3–4. (⁎p<0.05 and **p<0.01 compared with control).
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f0015: Ang II stimulated mitochondrial superoxide production in live hVSMC. Cells were pre-incubated with Ang II (1×10−7 mol/L) for 1 h then loaded with MitoSOX (5 µmol/L) for 10 min at 37 °C. Cells were washed to remove excess probe prior to measurement of fluorescence. Bars represent mean+SD, n=3–4. (⁎p<0.05 and **p<0.01 compared with control).

Mentions: The possible contribution of mitochondria to cellular following Ang II stimulation was investigated using mito-SOX as a superoxide reporter in live hVSMC (Fig. 3). Both tert-BHP and Ang II stimulated mitoSOX fluorescence by 1.5–2.0 fold compared to the control indicating that mitochondria within cells produce superoxide in response to Ang II.


A role for mitochondrial oxidants in stress-induced premature senescence of human vascular smooth muscle cells.

Mistry Y, Poolman T, Williams B, Herbert KE - Redox Biol (2013)

Ang II stimulated mitochondrial superoxide production in live hVSMC. Cells were pre-incubated with Ang II (1×10−7 mol/L) for 1 h then loaded with MitoSOX (5 µmol/L) for 10 min at 37 °C. Cells were washed to remove excess probe prior to measurement of fluorescence. Bars represent mean+SD, n=3–4. (⁎p<0.05 and **p<0.01 compared with control).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814954&req=5

f0015: Ang II stimulated mitochondrial superoxide production in live hVSMC. Cells were pre-incubated with Ang II (1×10−7 mol/L) for 1 h then loaded with MitoSOX (5 µmol/L) for 10 min at 37 °C. Cells were washed to remove excess probe prior to measurement of fluorescence. Bars represent mean+SD, n=3–4. (⁎p<0.05 and **p<0.01 compared with control).
Mentions: The possible contribution of mitochondria to cellular following Ang II stimulation was investigated using mito-SOX as a superoxide reporter in live hVSMC (Fig. 3). Both tert-BHP and Ang II stimulated mitoSOX fluorescence by 1.5–2.0 fold compared to the control indicating that mitochondria within cells produce superoxide in response to Ang II.

Bottom Line: Angiotensin also resulted in an increase in mitoSOX fluorescence indicating stimulation of mitochondrial superoxide.Significantly, the induction of senescence by angiotensin II was abrogated by rotenone and by the mitochondria-targeted superoxide dismutase mimetic, mitoTEMPO.These data suggest that mitochondrial superoxide is necessary for the induction of stress-induced premature senescence by angiotensin II and taken together with other data suggest that mitochondrial cross-talk with NADPH oxidases, via as yet unidentified signalling pathways, is likely to play a key role.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester LE3 9QP, UK.

ABSTRACT
Mitochondria are a major source of cellular oxidants and have been implicated in aging and associated pathologies, notably cardiovascular diseases. Vascular cell senescence is observed in experimental and human cardiovascular pathologies. Our previous data highlighted a role for angiotensin II in the induction of telomere-dependent and -independent premature senescence of human vascular smooth muscle cells and suggested this was due to production of superoxide by NADPH oxidase. However, since a role for mitochondrial oxidants was not ruled out we hypothesise that angiotensin II mediates senescence by mitochondrial superoxide generation and suggest that inhibition of superoxide may prevent vascular smooth muscle cell aging in vitro. Cellular senescence was induced using a stress-induced premature senescence protocol consisting of three successive once-daily exposure of cells to 1×10(-8) mol/L angiotensin II and was dependent upon the type-1 angiotensin II receptor. Angiotensin stimulated NADPH-dependent superoxide production as estimated using lucigenin chemiluminescence in cell lysates and this was attenuated by the mitochondrial electron transport chain inhibitor, rotenone. Angiotensin also resulted in an increase in mitoSOX fluorescence indicating stimulation of mitochondrial superoxide. Significantly, the induction of senescence by angiotensin II was abrogated by rotenone and by the mitochondria-targeted superoxide dismutase mimetic, mitoTEMPO. These data suggest that mitochondrial superoxide is necessary for the induction of stress-induced premature senescence by angiotensin II and taken together with other data suggest that mitochondrial cross-talk with NADPH oxidases, via as yet unidentified signalling pathways, is likely to play a key role.

Show MeSH
Related in: MedlinePlus